feat(12-02): wire all template strings to Alpine i18n store

- dashboard.html: headings, quick actions, empty states wired to x-text
- printers.html: h1, add button, h2 wired to x-text
- printers_new.html: all form labels (span pattern), options, submit buttons wired
- clients.html: headings, label, submit button wired
- client_detail.html: back link, section heading wired
- drivers.html: all headings, label, buttons, spinner wired
- packages.html: heading, description, table headers, empty state wired
- printer_detail.html: all dt/dd, section headings, copy buttons, script/export links wired with conditional Jinja2 for color/collate/client
- partials/printer_list.html: table headers, Yes/No cells (Alpine ternary), delete button wired
- partials/printer_edit_modal.html: edit trigger, modal title, all labels (span pattern), options, save/cancel wired
- partials/client_list.html: empty state, table headers wired
- partials/driver_list.html: table headers, unknown values, empty state wired
- Fix test_printers_library_no_form: check form element attribute instead of UI label string (now in i18n dict)

imptune/templates/packages.html

@@ -1,18 +1,18 @@
 {% extends "base.html" %}
 
 {% block content %}
-<h1>Packages</h1>
-<p>Printers with drivers assigned — ready for deployment package export.</p>
+<h1 x-data x-text="$store.i18n.t('packages_title')">Packages</h1>
+<p x-data x-text="$store.i18n.t('packages_description')">Printers with drivers assigned — ready for deployment package export.</p>
 
 {% if printers %}
   <figure>
     <table role="grid">
       <thead>
         <tr>
-          <th scope="col">Printer</th>
-          <th scope="col">Client</th>
-          <th scope="col">Driver</th>
-          <th scope="col">Downloads</th>
+          <th scope="col" x-data x-text="$store.i18n.t('printer_col')">Printer</th>
+          <th scope="col" x-data x-text="$store.i18n.t('client_col')">Client</th>
+          <th scope="col" x-data x-text="$store.i18n.t('driver_col')">Driver</th>
+          <th scope="col" x-data x-text="$store.i18n.t('downloads_col')">Downloads</th>
         </tr>
       </thead>
       <tbody>
@@ -32,6 +32,6 @@
     </table>
   </figure>
 {% else %}
-  <p class="empty-state">No package-ready printers yet. Assign a driver to a printer to enable package export.</p>
+  <p class="empty-state" x-data x-text="$store.i18n.t('no_packages_ready')">No package-ready printers yet. Assign a driver to a printer to enable package export.</p>
 {% endif %}
 {% endblock %}